A joint theoretical-experimental study is proposed of non-enzymatic protonation reactions of small molecules occurring in blood plasma, as a non-specific biological, tool for controlling the bioactivity of protonatable molecules such as amines. Carbonic acid--- until very recently thought to be unimportant in this context, together with lacti acid, are argued to be likely the most important protonating agents in the blood plasma. This differs from the conventional wisdom that most protonation reactions occur in blood plasma through interaction with (H+)aq. As a particular focus, carbonic acid chemistry will be studied in the context of the bicarbonate/CO2 buffer, which determines and stabilizes blood pH at about 7.4. The primary goal of the research is to support this new image, via state of the art computations and experiments. In particular, computational studies will realistically capture the nature of liquid aqueous environment and generate realistic reaction pathways for acid-base proton transfers. Parallel cutting edge ultrafast spectroscopy experiments will directly measure the protonation rates. Further goals supporting the primary goal wil be the determination and deeper understanding of the mechanism and reaction rate of acid-base proton transfer and application of this fundamentally important understanding to carbonic and lactic acid chemistry in blood plasma. The research program's results should have an important impact in many areas in biology, pharmacology and medicine, such as comprehending the bioactivity of scores of small protonatable molecules of proven bioactivity transferred through the blood system until they interact with their designated target, improving drug delivery. The proposed research will result in the training of several graduate students at Boulder and BGU in frontier level experiment and theory in an area of high biophysical significance. It addresses basic biophysics/biochemistry ideas from a new perspective on a textbook level. Results will be used in education venues at Boulder and BGU, including an Honors General Chemistry course and Biophysical Program courses at Boulder, and in the Boulder popular science outreach 'CU Wizards' series for children of ages 5-15. More generally, the results will be of use to a very broad community of scientists and we will review its novel aspects in broad- coverage scientific journals and make them available for the general public. ! PUBLIC HEALTH RELEVANCE: Research on buffering is an important property in biological systems. Carboxylic acids, such as carbonic acid play an important role in blood buffer. The outcome of this research will considerably enhance our understanding of the non-enzymatic protonation reactions in the blood buffer and the phenomenon of the 'mobile buffers. This project has an important impact in many areas in biology, pharmacology and medicine, such as comprehending the bioactivity of scores of small protonatable molecules of proven bioactivity, which are transferred through the blood system until they interact with their designated target, and improving drug delivery.